<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./lib/vue-2.4.0.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" v-model="n1">

        <select v-model="opt">
            <option value="+">+</option>
            <option value="-">-</option>
            <option value="*">*</option>
            <option value="/">/</option>
        </select>

        <input type="text" v-model="n2">

        <input type="button" value="=" @click="calc">

        <input type="text" v-model="result">

    </div>

    <script>
        var vm = new Vue({
            el: '#app', 
            data: {
                n1: 0,
                n2: 0,
                result: 0,
                opt: '+',
            },
            methods: {
                // 计算器算数的方法
                calc() {
                    // 逻辑：
                    switch(this.opt) {
                        case '+':
                            this.result = parseInt(this.n1) + parseInt(this.n2)
                            break;
                        case '-':
                            this.result = parseInt(this.n1) - parseInt(this.n2)
                            break;
                        case '*':
                            this.result = parseInt(this.n1) * parseInt(this.n2)
                            break;
                        case '/':
                            this.result = parseInt(this.n1) / parseInt(this.n2)
                            break;
                    }
                }
            }
        });
    </script>
</body>
</html>